I have a new PC with a Samsung SSD830 with 256GB and installed Ubuntu 12 two weeks ago.
I checked the disk alignment, but that was correct.
From the first day it gets slower after a while of usage.
I see it at the build time of my project or with
dd if=/dev/zero of=/tmp/output bs=8k count=10k; I get after booting 400MB/s write speed, and when I feel it is slow it is around 1.5MB/s.
When I reboot the PC, it is fast again. Is it a hardware failure? Are there any other suggestions what I can try? (tried sync command when it was slow)
EDIT: I activated auto trim as well, and did a manual trim what did not help
UUID=7b198f7a-d783-4ff3-97a0-b06186d0bb8e / ext4 noatime,nodiratime,discard,errors=remount-ro 0 1
UUID=8d937ac8-8286-4bf8-984d-69836d30ee88 none swap sw 0 0
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0
I thought it may be the home directory encryption, but without it is still getting slow.
I looked with iotop while he was writing but only the
dd command was shown
syslog contained no sda,
dmesg output was
[ 0.907090] sd 0:0:0:0: [sda] 500118192 512-byte logical blocks: (256 GB/238 GiB) [ 0.907137] sd 0:0:0:0: [sda] Write Protect is off [ 0.907138] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 0.907146] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 0.907732] sda: sda1 sda2 < sda5 > [ 0.908058] sd 0:0:0:0: [sda] Attached SCSI disk [ 0.969494] EXT4-fs (sda1): INFO: recovery required on readonly filesystem [ 0.969499] EXT4-fs (sda1): write access will be enabled during recovery [ 1.580308] EXT4-fs (sda1): recovery complete [ 1.581925] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null) [ 1.696890] Adding 16737276k swap on /dev/sda5. Priority:-1 extents:1 across:16737276k SS [ 1.957517] EXT4-fs (sda1): re-mounted. Opts: discard,errors=remount-ro